Improvements to electronic displays now allow them to be used in outdoor environments for informational, advertising, or entertainment purposes. While displays of the past were primarily designed for operation near room temperature, it is now desirable to have displays which are capable of withstanding large surrounding environmental temperature variations. For example, some displays are capable of operating at temperatures as low as −22 F and as high as 113 F or higher. When surrounding temperatures rise, the cooling of the internal display components can become even more difficult.
Additionally, modern displays have become extremely bright, with some backlights producing 1,000-2,000 nits or more. Sometimes, these illumination levels are necessary because the display is being used outdoors, or in other relatively bright areas where the display illumination must compete with other ambient light. In order to produce this level of brightness, illumination devices and electronic displays may produce a relatively large amount of heat.
Still further, in some situations radiative heat transfer from the sun through a front display surface can also become a source of heat. In some locations 800-1400 Watts/m2 or more through such a front display surface is common. Furthermore, the market is demanding larger screen sizes for displays. With increased electronic display screen size and corresponding front display surfaces, more heat will be generated and more heat will be transmitted into the displays.
Exemplary modern displays have found some effective means for cooling the electronic displays which may be used in high ambient temperatures and/or in direct sunlight. Some modern displays may move some type of cooling gas with a fan assembly, either circulating within the display (closed loop) or passing through the display (ingested/exhausted or open loop). Typical designs would measure the temperature within the display and engage the cooling fans once the temperatures within the display reach a predetermined threshold. However, it has been found that electronic displays typically have a large amount of thermal inertia and large amounts of power are required to reverse the increase in temperature and cool the display. In other words, it is much harder and requires much more energy to cool the display once the temperature within the display has actually risen. Energy consumption has become a major concern with large electronic displays and it is desirable to limit and/or reduce their overall energy consumption as much as possible without effecting its performance.
Thus, it is now desirable to predict when and to what extent the display will rise in temperature, and preemptively engage the cooling fans so that the cooling gas can begin flowing and mitigate any potential rise in temperature.